Hypersonic Technology Demonstrator Vehicle (HSTDV)/ Avatar (Rebirth)
AvatarAn eight-meter technology demonstrator is being built by the Defense Research & Development Laboratory (DRDL) in Hyderabad and is due to be tested sometime in the coming months. The demonstrator vehicle, being developed in cooperation with Israeli Aerospace Industries (IAI), will be powered by a "Scramjet" engine that takes in oxygen from the atmosphere and burns liquid hydrogen.

The hypersonic prototype will apparently be a precursor to DRDO's Aerobic Vehicle for Hypersonic Aerospace Transportation (AVATAR).

According to senior DRDO officials, the primary function of the vehicle is to act as a "reusable missile launcher, one which can launch missiles, land ... and be loaded again for more missions."

The proposed AVATAR will be able to take off and land like an aircraft and will also be capable of placing a payload of 1,000kg in low-earth orbit.

AVATAR would take off horizontally like conventional airplanes from conventional airstrips using turbo-ramjet engines that burn air and hydrogen. Once at a cruising altitude, the vehicle would use scramjet propulsion to accelerate from Mach 4 to Mach 8.

In this hypersonic cruise phase, an on-board system will collect air from which liquid oxygen will be separated. The liquid oxygen collected then would be used in the final flight phase, when the rocket engine burns the collected liquid oxygen and the carried hydrogen to attain orbit.

Re-usable Launch Vehicle The vehicle will be designed to permit at least a hundred re-entries into the atmosphere.

The non-military version, a Re-usable Launch Vehicle (RLV), is similar in concept and has the Indian Space Research Organisation as the lead development agency.

India Plans Lunar Landing Using Scramjet Hypersonic Space PlaneThe United States, Russia, India, Japan and China have all announced plans to send astronauts back to the Moon around 2020. India's space agency, although lacking the level of funding found in the US and Japan, has an ambitious plan for the next decade.

In a statement made this spring by India's then
president, A.P.J. Abdul Kalam, the country wants to launch its first lunar orbiter, the Chandraayan-1, in early 2008 and a manned mission to the moon sometime near the end of the
next decade.

The Indian space agency is now working on a revolutionary, reusable launch vehicle (RLV) that takes an innovative approach using a scramjet "hyperplane" according to Kalam. India's scramjet RLV, Kalam asserted, will provide the "low-cost, fully reusable space transportation" that has previously "denied mankind the benefit of space solar-power stations in geostationary and other orbits," Technology review reports.

A scramjet is a type of jet that uses a supersonic flow in the combustor and consists of a constricted tube through which inlet air is compressed by the high speed of the vehicle, a combustion chamber where fuel is combusted and a nozzle through which the exhaust jet leaves at higher speed than the inlet air.

This new design could offer many applications, like low-cost satellite launching and manned missions to space and will be capable of high speeds, in excess of Mach 10, which means that it could make the flight between Sydney and London in just two hours.

The first flight of the Hypersonic Technology Demonstrator Vehicle (HTDV), a protoype for the scramjet RLV named Avatar, is scheduled for the end of next year, and if it is successful, it will be a revolution in space exploration.

Avatar will be a light aircraft, weighing only 25 metric tons and to get into space, it will use liquid hydrogen to fuel the turbo-ramjet engines, 60 percent of which will be used to defeat Earth's gravity and ascent to a cruising altitude.

"The Avatar RLV project will enable the Indian program to leap ahead of the Chinese nostalgia trip. Once low cost to orbit comes alive, it will drive cheaper methods of doing all our unmanned activities in space," said Gregory Benford, an astrophysicist at the University of California, Irvine, and an advisor to NASA and the White House Council on Space Policy.

A surprising entrant in this race to develop a commercially viable scramjet based hyperplane is our own country, India. The 'Aerobic Vehicle for hypersonic Aerospace TrAnpoRtation' (AVATAR) is a hyperplane concept from India. It is planned to be the size of a MiG-25 fighter and would be capable of delivering a 500 kg to 1000 kg payload to low earth orbit at a rather petty rate of Rs 3500/- per kg assuming an airframe life of 100 launches.
Weighing only 25 tonnes - 60 per cent of which is liquid hydrogen fuel - Avatar is said to be capable of entering into a 100-km orbit in a single stage and launching satellites weighing up to one tonne.

AVATAR would take off horizontally like conventional airplanes from conventional airstrips using turbo-ramjet engines that burn air and hydrogen. Once at a cruising altitude, the vehicle would use scramjet propulsion to accelerate from Mach 4 to Mach 8. AVATAR or Avtar was first announced in May 1998 at the 'Aero India 98' ehxibition held at Bangalore.
The AVATAR is being developed by India's Defence Research and Development Organisation or DRDO. Air Commodore Raghavan Gopalaswami(Retd.), former chief of Bharat Dynamics Ltd, Hyderabad (which produces India's military missiles) is heading the project. The initial development budget is only $5 million, but project supporters claim that the vehicle can be built in ten years with total funding of under $2 billion. Designers admit, however, that international assistance would be required for the project to reach its goal.

In addition to the DRDO team working on the conceptual design, development of technology components is being undertaken by as many as 23 academic institutions (IITs, IISc etc) in India as well. A Hyderabad-based private company CIM Technologies is also participating in the project.

Both the scramjet engine concept and the liquid oxygen collection process have already undergone successful tests at DRDO and at the Indian Institute of Science, Bangalore. DRDO has approved further testing of the liquid oxygen process and assigned a team to conduct a detailed review of the vehicle’s design.

Currently DRDO plans to build and fly a scaled down version called Light-Avatar (LAVATAR?), weighing just 3 tonnes at take off. To be built by CIM technologies by 2006, mini-Avatar will not go into space but will demonstrate all technologies used in Avatar including oxygen collection. It will use the India's Kabini jet engine.

It is claimed that the real AVATAR would be viable by as early as 2013-2015(!) - provided international co-operation is available.

A scramjet that cruises at 17290 km/hr
Saturday August 9 2008 15:53 IST

An Indian double has caught global attention in the hypersonic race for cheap and cost effective launch technology.

Bidding for their rightful place among the world’s majors, two of the country’s premier agencies are in the advanced stages of proving scramjet (supersonic combustion ramjet) technology to meet their respective strategic needs.

While the Indian Space Research Organisation (ISRO) is working on the Reusable Launch Vehicle (RLV) for launching satellites, the Defence Research and Development Organisation (DRDO) is dreaming about a Hypersonic Technology Demonstrator (HSTD) to carry a range of weapons faster and farther.

Both have set a 2010 deadline. And both are in the pre-fabrication stage. But ISRO has the edge as it has already carried out a seven-second experimental combustion of a test engine. To state that both the projects are progressing at somewhat the same pace won’t be far off the mark.

But there’s a remarkable design difference between the RLV and the HSTD. ISRO’s hypersonic plane, being built at the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, is a winged body while the HSTD is a sleeker structure. The only common architecture, perhaps, is the air intake scoop at the front through which atmospheric air will be sucked in before oxygen is separated from it to oxidise the onboard fuel.

This is how the scramjet bypasses the need to carry an oxidiser on board. In a conventional rocket, the fuel and oxidiser are stored separately and burnt in a regulated combustion of eight grams of oxygen to one gram of fuel. But in the scramjet, oxygen is isolated from the air, compressed and introduced to a stream of fuel.

To ensure that sufficient oxygen is ingested for a self-sustaining flight, the scramjet must get to supersonic speeds before going ahead with its designated mission of launching a satellite for ISRO or delivering a warhead for DRDO.

This speed is achieved by coupling the scramjet to a conventional rocket during the initial phase of the flight. "We will mount the RLV prototype on a sounding rocket (S9). The rocket will speed it up to Mach 5 before the body is allowed to surf and suck air for onboard combustion. This process fires the scramjet and propels the payload to the desired orbit at speeds between Mach 8 and 10," says VSSC director K Radhakrishnan.

The DRDO plans to use a core-alone Agni stage (S1). The capsule containing the HSTD will ride on Agni to stratospheric heights. After the first stage separates, the capsule shifts to a horizontal alignment and opens up to allow the HSTD to skim the atmosphere and breathe air.

“We’re in an advanced stage. The shock tunnel test will soon be conducted. Our plan is to have a 400-second flight by 2009,’’ says M S Sundareshan, technical adviser at the Defence Research and Development Laboratory, Hyderabad. The DRDL is currently firing its test engine in a ground facility.

“The initial results are promising. We achieved significant thrust value,” says Sundareshan, adding that achieving hypersonic levels is a challenge that no nation except the US has met. The DRDO needs such speeds for weapon delivery at very great distances. The job is now done by Inter Continental Ballistic Missiles.

But like space rockets, ICBMs are a very costly chemical proposition. “The hyperplane can fly in at fast speeds, fire the missile or launch the warhead and return. The reusability will reduce our costs significantly,” says DRDL director Dr Venugopalan.

Cost figures in ISRO’s calculus as well. “The cost of launching a satellite using conventional rockets like the PSLV or GSLV is $25,000 to $28,000 per kg. The scramjet can reduce it to $500. This will make any nation with such a technology a launch destination,” says Radhakrishnan.

One great attraction is that the RLV can be brought back and reused. “The conventional rocket is expendable. Each stage burns out as the payload soars. But the RLV will come back after its mission,” he says.

ISRO will land the RLV on the sea using parachutes. But a project to facilitate its landing like an unmanned aircraft is on the anvil. DRDO also plans to land it like an aircraft. “We’ve a few UAV projects going where this technology is being experimented with. It can be integrated with the HSTD,” sources say.

Another frontier that scramjet research has opened up is advanced metallurgy. “We’re talking about a craft that moves at great speeds, breaks off from the atmosphere and re-enters, weathering high temperatures and atmospheric friction. There are several new alloys being developed. Apart from their use in scramjet vehicles, this research will impact the whole gamut of strategic metallurgy,” says Dr G Malakondaiah, director of the Defence Metallurgical Research Laboratory, Hyderabad.

India is experimenting with silica-carbon-silica and nickel-based alloys to cover the scramjet. Both alloys have high thermal resistance. A prototype using these alloys will be subjected to wind tunnel tests to gauge their strength against the vagaries of the atmosphere and beyond.

It is but natural for anyone to wonder why two Indian agencies are developing the same technology in parallel, with so much, except the sophisticated nature of the end-use, in common. ISRO insiders blame it on the absence of a pro-active culture within DRDO’s portals; the latter finds fault with ISRO’s big brother attitude.

“It’s the typical Indian defence story,” says one former top gun of ISRO. “In a way, it’s a blessing in disguise. Whoever proves it first will attract global attention. With the country inching closer to the concept of aerospace strategic forces, there will be a lot of give and take once the technology is proved indigenously,” he adds.

And the scramjet will place India in a league of nations that includes the US, Japan, China, Russia, Australia and Europe where this nascent technology is the latest scientific fad.

India's first scramjet technology demonstrator will be flight-tested next year, four years later than planned and having failed to meet two previous targets, by the government-run Defence Research and Development Laboratory in Hyderabad.

The Indian military wants to use scramjet systems for a hypersonic missile. The first demonstrator flight test will be carried out at India's integrated test range on its east coast.

Flight International revealed in 2004 that the country had planned a 2006 scramjet test. When that failed to take place, Israel Aerospace Industries announced in 2007 it was helping India develop the technology for a first flight in 2008.

"The biggest challenge [will] be how to sustain stable combustion during the high-speed trans-atmospheric flight of the vehicle," says sources at the Indian government's Defence Research and Development Organisation, under which the laboratory operates.

India has longer-term plans to use scramjet technology for its proposed 25,000kg (55,000lb) spaceplane called Avatar, the Sanskrit word for a god who appears in bodily form on Earth. The spaceplane would ferry civilian and military satellites of about 1,000kg into a low Earth orbit.

Hold your horses guys. No need to get carried away. The AVATAR is still in the design phase and we'll have to overcome huge obstacles before this project sees the light of day.
While I wish our scientists the very best, a word of caution. India's problems in materials science are well known.
For e.g. Absence of Single Crystal Blade technology, which was one of the reasons for setbacks in the Kaveri which was a Low Bypass Turbofan. Nothing Hi-tech.
I do not know much about jet engines but I would guess that there must be several more such problems we would have to overcome before we get the hi-tech Scramjet running.

much further development is needed but from reports i have read other nation(s) are also involved, i won't say who but the status of the project is still unnknown ,and many more years to go, no news has been released in a long time.

Hyderabad: The Israel Aerospace Industries (IAI) and India's Defence Research and Development Organisation are working together on a hypersonic technology demonstrator vehicle (HSTDV). The work is moving apace with the intention of conducting a test flight sometime in 2008.
DRDO is developing the HSTDV to demonstrate a kerosene-fuelled scramjet engine capable of powering air-breathing vehicles to a speed of Mach 6.5-7. It is the stated aim of the project to reduce the cost of putting payloads into orbit by a factor of 100, i.e. to $200/kg ($90/lb). Some of the wind tunnel testing for the project is being performed by the IAI.

India is already conducting extensive research on special materials for thermal protection of the HSTDV, including carbon-carbon composites, nickel-based superalloys, niobium alloys and high thermal conducting copper alloy.

Indo-Israeli RAM/SCRAMJET cooperation
Meanwhile, at a prestigious scientific conference dealing with "High speed trans-atmospheric air and space transportation" conducted in the Indian city of Hyderabad from June 29-30 and inaugurated by the Indian president, and distinguished aerospace scientist Dr APJ Abdul Kalam, some hints were dropped about the Indo-Israeli cooperation in this area.

The Israel Aerospace Industries (IAI)'s president & CEO, Itzhak Nissan, was invited as a guest of honor at the event in deference to his personal activities in India, where he leads a number of advanced technological projects.

Speaking on the occasion, Dr Kalam mentioned that Ram/Scramjet engine technology had already been designed and tested by both Russia and the US since the 1960s and most recently by the US through the Flight Technology Demonstrator, X-43. The president also mentioned that India too had "â€¦designed and tested scramjet engines, both kerosene fueled and hydrogen fueled, on ground test facilities.

In his speech, the President of India, Dr APJ Abdul Kalam, praised the growing cooperation between India and Israel at large and the cooperation with IAI in particular.

In his lecture, IAI's president & CEO, Itzhak Nissan, said "IAI, the leading aerospace industry in Israel, is partner for a wide range of commercial and military projects in India. In these projects, we manage to express the capabilities that are mutual to both countries. We are proud to be partners with the superb capabilities demonstrated by the Indian development and manufacturing teams working on some of the most advanced projects in the world."

Mr. Nissan added that: "IAI expresses profound appreciation for the high level of scientific level and motivation that can be found at India's research institutions and aerospace industry."

During the conference, VK Saraswat, the chief controller (R&D), DRDO and chairman of the Aeronautical Society of India, made a presentation on the commercial Hyper Sonic Technology Demonstrator Vehicle. The ground test for HTDV scramjet propulsion system using kerosene as fuel has been conducted by DRDO scientists at a high speed material testing laboratory abroad and the results have been encouraging, he told reporters at the event.

This would be a reference to the wind tunnel and other experiments being carried out by the IAI.

Last March, engineers from Pratt & Whitney Rocketdyne (PWR) gathered in the control room of a high-temperature tunnel at NASA's Langley Research Center in Virginia. After a countdown, a jet of blue flame fueled by methane gas roared down the 12-foot length of the tunnel. A low rumble crept into the control room. It sounded like a rocket firing, which actually wasn't far from the truth.

"Okay to inject," a test director announced when the flame had reached full force. An angular pedestal covered in bolted copper plates rose from the floor of the chamber, placing an experimental scramjet engine called the X-1 into the inferno. "AOA modulating," called the test director as the engine tilted slightly. "Model on centerline." Then, "We are in ignition." And with that, an exhaust flame even hotter than the 2,000°F-plus methane jet around it began to dance behind the activated engine, growing brighter as it ramped up to full thrust. After one minute, the engine shut down and descended through the floor.

The test was part of the X-51A Flight Test Program, a research project funded by the Air Force Research Laboratory and the Defense Advanced Research Projects Agency (Darpa), the Pentagon's research arm. The X-51A project is, in turn, one piece of a global effort—part collaboration, part race—to build jet-powered aircraft that fly as fast as rocket ships. And the technology that will make this breakthrough possible is the scramjet, an engine that inhales air at tremendous speeds, squeezes the air until it's thousands of degrees hot, and then mixes that air with fuel to generate massive thrust at higher speeds than any other jet-engine design.

The X-1 scramjet engine, which will eventually power the X-51A aircraft, is the most advanced scramjet engine ever built. The blowtorch blasting through the chamber was meant to simulate the extreme heat generated by flying faster than Mach 6. In all, the team at Langley would repeat this test 44 times. "We tested it at Mach 4.6, 5.0 and 6.5," says Curtis Berger, the X-51A program manager at PWR. "The amount of time that this thing was actually running and creating thrust was just about 17.8 minutes." He pauses to let that sink in. "Over 17 minutes of time on this engine. That's a lot of time for a scramjet engine."

To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines; the fastest fighter planes barely crack Mach 1.6. Scramjets, on the other hand, can theoretically fly as fast as Mach 15—nearly 10,000 mph.

This could mean two-hour flights from New York to Sydney. It could also mean missiles capable of hitting targets on another continent at a moment's notice, and when you put it that way, it's not surprising that militaries around the world—the U.S., Australia, China and perhaps others—are trying to build them. After decades on the drawing board, it seems scramjet technology is finally about to arrive.

A Match in a Hurricane

Ordinary jets have a major limitation: They can't go faster than Mach 3 without their turbine blades melting. Rocket ships can reach Mach 25, but they have to carry tremendous amounts of liquid oxygen to burn their fuel. The space shuttle, for example, weighs only 165,000 pounds empty, but it must carry 226,000 pounds of liquid hydrogen and 1.4 million pounds of liquid oxygen to reach orbit.

An air-breathing jet engine with no moving, meltable parts, such as a scramjet, can solve these problems. A scramjet is an advanced form of a "ramjet," an engine that takes the air rushing into the engine and "rams" it into the combustion chamber, creating intense pressures that can sustain combustion at the furious rate that Mach-3-plus speeds demand. But ramjets have limits too. The air entering the engine has to be slowed to subsonic speeds for it to run efficiently. And that air is so hot that no matter what measures are taken to cool it, a ramjet-powered craft must stay under Mach 5 to keep from disintegrating.

But a scramjet—a "supersonic combustion ramjet"—changes things. A scramjet does away with the diffuser that a ramjet uses to slow down incoming air, allowing the air to move through the engine at supersonic speeds so it can fly above Mach 5. The tradeoff: A scramjet engine in flight is a delicate system. Achieving balanced combustion at those speeds is an engineering challenge often compared to keeping a match lit in a hurricane.

So far, the most public scramjet project has been the National Aerospace Plane, or NASP. Unfortunately, it was a spectacular failure. Announcing the project in his 1986 State of the Union address, President Reagan called it "a new Orient Express" that would be able to reach Tokyo from Dulles Airport in two hours; the goal was to have it running by the late 1990s. NASP was meant to be all things to all customers—America's next space shuttle as well as the Air Force's next bomber and the next big thing in passenger travel. But by 1994, it appeared that research had stalled, and President Clinton canceled NASP. That might have been a good thing. "We didn't stop our research," says Charlie Brink, a scramjet program manager at the Propulsion Directorate at the Air Force Research Laboratory. "We reevaluated it and said: Now that we're not trying to make a Mach-0-to-25 vehicle take off from a runway, let's take the technical problem and break it down into more manageable chunks."

"What you're seeing now is a transition of the technology out of the laboratories into the flight-test domain," says David Van Wie, a scramjet research scientist at the Johns Hopkins University Applied Physics Laboratory. Armed with a new understanding of hypersonic aerodynamics and air-breathing propulsion, Van Wie says, "it's really to the point that people who work in the field feel they're ready to take the steps into flight test, experimentation and demonstration."

Escape from the Lab

In 2002, Australian researchers with the HyShot program at the University of Queensland's Centre for Hypersonics made history by conducting the world's first scramjet "flight." They strapped a small scramjet engine into the nose cone of a solid-fuel rocket and launched it to the edge of space. Then, some 200 miles up, the rocket dropped off, the scramjet shed its protective fairing and, as planned, nosed over and plummeted back toward Earth at thousands of miles an hour. At an altitude of 20 miles, the scramjet engine kicked in, firing for five seconds and reaching Mach 7.6, or more than 5,000 mph, before slamming into the ground. It wasn't graceful, but it was a historic achievement and a scientific success—a low-cost way to gather data from a scramjet while subjecting it to brutal heat and incredible velocity outside of a wind tunnel.

Since then, a loose federation of researchers from NASA, the Air Force, the Navy, Darpa and the University of Queensland, working on a variety of projects, has conducted a number of tests outside the lab. So far, no engine has pulled off more than a few seconds of sustained flight. But there have been major breakthroughs along the way. In 2004, NASA's unmanned X-43A—a disposable, rocket-boosted craft that was launched from a moving airplane—reached Mach 9.6, setting the world speed record for a jet-powered aircraft. It took only 10 seconds of scramjet power to get it up to that speed. And HyCause, the program that succeeded HyShot, conducted tests in Australia last summer that reached Mach 10, but only for three seconds.

A scramjet that can stay lit for several minutes could power a hypersonic long-range missile. That, at least, is the idea behind a joint Darpa and Navy project called Hypersonics Flight Demonstration, or HyFly. Last fall, the program carried out the latest in a series of test flights in which a scramjet was dropped from an F-15 fighter jet off Point Mugu in California and boosted to operating speed by rocket. The goal was to reach Mach 6 and keep the scramjet going for 100 seconds or more. (It didn't make it that time, but the tests will continue, program officials say.)

A payload-carrying, piloted craft that can take off and land under its own power will need an engine that can produce power for a lot longer than 100 seconds, though. Breaking that barrier is the goal of the X-51A Flight Test Program, whose engineers spent much of last year torching its X-1 engine design in Langley's high-temperature test tunnel. So far, the X-1 has had to take more punishment than any scramjet engine ever built. It's made of a steel-nickel alloy that stays strong up to 2,100°F, and its leading edges are coated in a heat-resistant carbon mesh. Even these materials aren't enough, though, so the X-1's engineers borrowed a technique from rocket designers, who typically circulate fuel—in this case, the same petroleum-based jet fuel that powered the SR-71—along channels within the engine's walls before it enters the combustor. This both cools the 3,000°F-plus combustor and preconditions the fuel, turning it into a hot gas that packs 10 percent more energy than it does in liquid form.

The X-51A's target is five minutes of uninterrupted scramjet-powered flight. If it works, longer-burning scramjets should quickly follow. "The five minutes of flight we're talking about is not limited by the propulsion system," Berger says. "That's just how much gas we have in the tank." On a modified vehicle with a bigger gas tank, that five minutes could easily turn into an hour or longer. And that, says Mike McKeon, PWR's manager of Hypersonic and Advanced Programs, is key. "This engine has demonstrated that the propulsion technology is ready for application," he says of the X-1. "It's no longer in the research-technology mode." Next-generation engines based on the X-1 are already being built at PWR's plant in Florida.

With any luck, sometime in 2009, the X51-A will shatter all previous records for sustained scramjet ignition. The PWR team imagines that a B-52 bomber will take off from Edwards Air Force Base in California's Mojave Desert, head toward the coast and, at 45,000 feet, drop the X-51A from the plane. A solid-fuel rocket attached to the X-51A will fire, blasting it up to 60,000 feet and past Mach 4.5, and then drop off to let the scramjet ignite. For five minutes, the scramjet will accelerate the X-51A to a peak speed past Mach 6 and an altitude above 80,000 feet. Then it will fly into the Pacific, its data safely telemetered to engineers on the ground.
The test will also mark the moment when scramjets move from flash-in-the-pan science experiments to useful tools. "This is an airplane," Berger emphasizes, "not just something where you light a scramjet and fire it and see where it goes. This is really beyond something you might do for a weapon application. The whole idea is to prove the practicality of a free-flying, scalable, scramjet-powered vehicle."

The Real Race Begins

The first true reusable, free-flying scramjet could be Darpa's HTV-3X. Also known as Blackswift, the unmanned vehicle looks like an alien spaceship, with black curves, a rapier-like prow and oval exhaust ports. It's still only in the planning stages as part of Darpa's Falcon program, but it could represent the biggest breakthrough in aeronautics since the jet engine itself. It will demonstrate for the first time all the technologies needed for a practical scramjet-powered aircraft by taking off and landing under its own power and running on scramjets as long as needed to complete its mission.

The HTV-3x could make its inaugural flight as early as 2012. Here's how a perfect mission would go: The unmanned craft taxis out of a hangar at Edwards Air Force Base. Its twin conventional turbine engines throttle up before it accelerates down the runway and climbs into the desert sky, followed closely by a chase plane. The chase plane keeps pace until shortly after the unmanned craft hits the speed of sound. At Mach 2, doors just within the jets' inlets close off the turbines and open the airflow to the scramjet engines, which fire out of the same nozzles used by the turbine jets. On the ground, engineers watch their bird hit Mach 6, twice as fast as any turbine- jet-powered craft ever built. The test completed, the craft slows to subsonic speed, switches to turbine jets, and lands back at Edwards, mission accomplished.

Darpa officials are keeping quiet about Blackswift for now. Spokesperson Jan Walker says no project engineers could give interviews for this article because "it's a very busy time for the program." But Pratt & Whitney Rocketdyne is already at work on the engine that HTV-3X will use—a combined-cycle turbine-scramjet engine—and although Lockheed Martin won't confirm it, the company's famously secretive Skunk Works division is widely believed to be building the vehicle itself.

Meanwhile, there's competition. Last July, engineers from China showed up at the American Institute of Aeronautics and Astronautics Joint Propulsion Conference in Cincinnati and revealed a growing scramjet research program of their own, including a new hypersonic wind tunnel in Beijing and work on rocket-powered combined-cycle scramjets. None of the American scramjet experts we talked to would discuss their reactions to the Chinese revelations. But Craig Covault, an editor at Aviation Week & Space Technology who reported on the conference, believes one of the main reasons the Chinese attended was to glean all available intel on Western scramjet research. "I would bet that they have a serious research program under way that has a lot more going on than just the few papers that they issued at this forum," Covault says. "The reason that they issued them was just kind of a message to the rest of the world that they are engaged in these high-tech things. It also allowed them to get the 500 or more other papers in propulsion technology of all kinds delivered at the conference."

Scramjet projects have failed before, and some of the initiatives under way today could fail too. But many researchers say that this time around, scramjets are for real. "Advanced propulsion technology has a development timescale that appears to be on the order of decades," says Johns Hopkins's Van Wie. "The first scientific paper on rockets was published in 1903, and rockets became practical during World War II, 40-some years later." He points to a seminal conference in 1960 during which researchers first hashed out the major challenges to building practical scramjets. "So if you look at that—1960 to now, 47 years or so—it's kind of on the same timescale to see this roll out." In other words, that two-hour flight to Tokyo just might be leaving sooner than you think.